**4. Renewable energy sources**

Back bone of the microgrid power supply is renewable energy sources. Most commonly used renewable energy sources are fuel cells, microturbines, solar, and wind. Fuel cells can produce power through electrochemical actions among oxygen and hydrogen. This reaction is highly effective and gives bi product as water and temperature. Due do this environment friendly bi products, this technology becomes popular compared to conventional diesel engines which are more expensive and pollute environment by releasing flue gases. Even though fuel cells are discovered in eighteenth century, it has been in use in late nineteenth century. Because of usage in commercial and domestic applications, fuels cells power technology become popular. Fuel cells have more advantages such as power quality, very

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**Figure 5.** *Wind turbines.*

**Figure 4.** *Bloom box servers.*

*Microgrid*

*DOI: http://dx.doi.org/10.5772/intechopen.88812*

high efficient, environment friendly, and modularity. Recent times in microgrid applications, fuel cells are very effective in replacing IC engine usage which makes microgrid environment free. Further fuel cell technology usage will reduce greenhouse gases and improved efficiency of the microgrid. Advancement in fuel cell technology leads to bloom box energy servers which convert fuel into electricity through electrochemical approach. Bloom box servers are available as building box as clusters ratings from hundred kilowatts to megawatts. Bloom box is highly

Wind energy is most promising sources of renewable energy source, which has more potential in future. Wind energy power plants are sustainable energy producers. Wind turbines play a vital role in supplying power along with fuel cells and solar cells to microgrids. Wind turbines are bundled into components such as rotor, generator, turbine blades, and driver or a coupling device as shown in **Figure 5**. As high speed rotates the blades, the air exerts aero dynamic forces will make the blades to turn the wind rotor. In turn rotor rotates the generator through gear box. Wind generators are mostly induction generators or permanent magnet generators

Solar power plant generation systems are conversion of sunlight into electric power

either directly using PV cells or indirectly using concentrated solar power plants.

efficient in power production, modular, and scalable (**Figure 4**).

which supplies power to the microgrid.

**Figure 4.** *Bloom box servers.*

*Research Trends and Challenges in Smart Grids*

The evolution of microgrid is able to provide solution to problem of integrating huge amount of micro-energy sources without affecting the main power supply from the power utility provider. With the intelligent controllers, microgrid works effectively with the existing power system distribution services to match the variable load demand. Some of the times, microgrid can act as an auxiliary for the main grid to support the distribution and utilization. With the support of protection systems is able to disconnect from the disturbance if there is any fault in main grid, and microgrid is able to operate in a standalone mode which improves the reliability and quality of the power to the consumer. Microgrid is a decentralized grid with improved efficiency, located near to the load, and capable of extracting power from distributed renewable

Consumers able to get advantages from microgrid because it is developed and utilized for the local needs in terms of temperature and energy consumption, able to provide uninterruptible power, highly reliable, reduced losses, and improved voltage profile. Apart from the power generation and distribution microgrid involves in storage, control of load profile and extracting energy from heat. The success behind microgrid is capability of the grid to have smooth mode change from

Back bone of the microgrid power supply is renewable energy sources. Most commonly used renewable energy sources are fuel cells, microturbines, solar, and wind. Fuel cells can produce power through electrochemical actions among oxygen and hydrogen. This reaction is highly effective and gives bi product as water and temperature. Due do this environment friendly bi products, this technology becomes popular compared to conventional diesel engines which are more expensive and pollute environment by releasing flue gases. Even though fuel cells are discovered in eighteenth century, it has been in use in late nineteenth century. Because of usage in commercial and domestic applications, fuels cells power technology become popular. Fuel cells have more advantages such as power quality, very

energy sources. Microgrid special features are highlighted in **Figure 3**.

**3. Microgrid benefits**

island to grid and vice versa.

**4. Renewable energy sources**

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**Figure 3.** *Microgrid features.*

**Figure 5.** *Wind turbines.*

high efficient, environment friendly, and modularity. Recent times in microgrid applications, fuel cells are very effective in replacing IC engine usage which makes microgrid environment free. Further fuel cell technology usage will reduce greenhouse gases and improved efficiency of the microgrid. Advancement in fuel cell technology leads to bloom box energy servers which convert fuel into electricity through electrochemical approach. Bloom box servers are available as building box as clusters ratings from hundred kilowatts to megawatts. Bloom box is highly efficient in power production, modular, and scalable (**Figure 4**).

Wind energy is most promising sources of renewable energy source, which has more potential in future. Wind energy power plants are sustainable energy producers. Wind turbines play a vital role in supplying power along with fuel cells and solar cells to microgrids. Wind turbines are bundled into components such as rotor, generator, turbine blades, and driver or a coupling device as shown in **Figure 5**. As high speed rotates the blades, the air exerts aero dynamic forces will make the blades to turn the wind rotor. In turn rotor rotates the generator through gear box. Wind generators are mostly induction generators or permanent magnet generators which supplies power to the microgrid.

Solar power plant generation systems are conversion of sunlight into electric power either directly using PV cells or indirectly using concentrated solar power plants.

**Figure 6.** *Solar power plants.*

Photovoltaic generation is systems, which convert the sunlight directly to electricity as shown in **Figure 6**. PV cell technology is very well established and used extensively in microgrid. The DC output of the connected PV cells is given as input to the inverter and AC power supply given to the load through inverter. The most common renewable energy source in the world is solar energy.

All microgrids are more effective in extracting local energy source is only from solar. The main advantages of these solar power plants are very less time required to design and install the power plant. These plants are highly modular, and it is good alternative for peak load demand. Since solar structures are static and no moving parts which gives no noise power plant status to solar power plants. Solar power plants are portable and mobile because of light weight. Since there is no moving part, PV generation systems are having longer life time which makes one of the attracting renewable energy sources connected with microgrid.

Microturbines and microhydro turbines are gas and hydro electric generators ranging in size from 25 to 500 KW connected with microgrid. These microturbines are very much useful in dealing with peak load demands for the microgrids. Biomass is also another renewable source contributing energy supply to microgrids located in remote villages or urban waste sources. The source materials are scrap lumper, forest debris, certain crops or manure, etc. Geo thermal power plants are recent renewable energy sources generating power from geo thermal energy. Geo thermal energy is a thermal energy stored in the earth is utilized. In future, microgrids are expected to add mini geo thermal power plants in its pool of distributed energy resources. In future, the other renewable energy power supply from tides of the sea and hot hydrogen fusion will be a part of microgrid energy sources.
